Allowance for Doubtful Accounts (Tables)
 12 Months Ended
Dec. 31, 2015
Receivables [Abstract]  
Summary of Allowance for Doubtful Accounts
The activity of the allowance for doubtful accounts for the years ended:
 
 
December 31,
 
 
2015
 
2014
 
2013
Balance at January 1,
 
$
3,942

 
$
4,709

 
$
4,798

Provision charged to income
 
2,772

 
241

 
851

Write-offs
 
(1,140
)
 
(772
)
 
(870
)
Currency
 
(198
)
 
(236
)
 
(70
)
Balance at December 31,
 
$
5,376

 
$
3,942

 
$
4,709